On Wed, Mar 21, 2007 at 03:23:28AM -0600, Eric W. Biederman wrote: > sukadev@xxxxxxxxxx writes: > > > From: Cedric Le Goater <clg@xxxxxxxxxx> > > Subject: [RFC][PATCH 06/14] Populate pid_nrs list with entry for init-pid-ns > > > > Create/destroy the pid->pid_nrs list - when allocating/freeing a struct pid. > > The pid_nrs list contains just a single struct pid_nr for now, (corresponding > > to init-pid-ns). > > > > To enable finding a process based on any of its pid_t values, replace the > > use struct pid_nr, rather than struct pid, in the pid_hash table. > > > > Finally, reimplement find_pid() and pid_nr() based on the pid_nrs list. > > > > Changelog: > > - [Serge Hallyn's comment]: Add comments on what pid->lock protects > > and that pid->nr will eventually go away. > > - [Eric Biederman and containers list comments]: Reworked patches > > to drop support for unsharing pid namespace and to replace > > struct pid with struct pid_nr in the pid_hash table. > > > > Signed-off-by: Cedric Le Goater <clg@xxxxxxxxxx> > > Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxx> > > --- > > include/linux/pid.h | 9 ------ > > kernel/pid.c | 73 ++++++++++++++++++++++++++++++++++------------------ > > 2 files changed, 50 insertions(+), 32 deletions(-) > > > > > @@ -242,50 +247,70 @@ struct pid_nr *alloc_pid_nr(struct pid_n > > */ > > pid_nr->pid = pid; > > > > + spin_lock_irq(&pidmap_lock); > > + hlist_add_head_rcu(&pid_nr->pid_chain, &pid_hash[pid_hashfn(nr)]); > > + spin_unlock_irq(&pidmap_lock); > > + > > Hmm. I think we really need to hash in some of the bits of the > pid_namespace so processes with identical pids don't get put on > the same hash chain. It isn't critical but it is a good idea. yes, can't hurt to distribute that a little, was already thinking about something like this: #define pid_hashfn(nr) hash_long((unsigned long)(nr ^ space), pidhash_shift) as the hash_long should distribute any changes quite evenly ... best, Herbert > Eric > _______________________________________________ > Containers mailing list > Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx > https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
